Re: [PATCH] libstdc++: Add pretty printer for std::initializer_list

[Jonathan Wakely <jwakely@redhat.com>]

On Sun, 24 Apr 2022 at 16:51, Philipp Fent via Libstdc++
<libstdc++@gcc.gnu.org> wrote:
>
> Re-using the std::span printer, this now shows the contents of the
> initializer list instead of the pointer and length members.

Nice, I've pushed this to trunk. Thanks!


>
> Signed-off-by: Philipp Fent <fent@in.tum.de>
> ---
>  libstdc++-v3/python/libstdcxx/v6/printers.py  | 23 +++++++++++++++++--
>  .../libstdc++-prettyprinters/cxx11.cc         |  6 +++++
>  2 files changed, 27 insertions(+), 2 deletions(-)
>
> diff --git a/libstdc++-v3/python/libstdcxx/v6/printers.py b/libstdc++-v3/python/libstdcxx/v6/printers.py
> index 6d8b765f2..48798b6c1 100644
> --- a/libstdc++-v3/python/libstdcxx/v6/printers.py
> +++ b/libstdc++-v3/python/libstdcxx/v6/printers.py
> @@ -1657,7 +1657,7 @@ class StdRegexStatePrinter:
>  class StdSpanPrinter:
>      "Print a std::span"
>
> -    class _iterator(Iterator):
> +    class iterator(Iterator):
>          def __init__(self, begin, size):
>              self.count = 0
>              self.begin = begin
> @@ -1686,7 +1686,24 @@ class StdSpanPrinter:
>          return '%s of length %d' % (self.typename, self.size)
>
>      def children(self):
> -        return self._iterator(self.val['_M_ptr'], self.size)
> +        return self.iterator(self.val['_M_ptr'], self.size)
> +
> +    def display_hint(self):
> +        return 'array'
> +
> +class StdInitializerListPrinter:
> +    "Print a std::initializer_list"
> +
> +    def __init__(self, typename, val):
> +        self.typename = typename
> +        self.val = val
> +        self.size = val['_M_len']
> +
> +    def to_string(self):
> +        return '%s of length %d' % (self.typename, self.size)
> +
> +    def children(self):
> +        return StdSpanPrinter.iterator(self.val['_M_array'], self.size)
>
>      def display_hint(self):
>          return 'array'
> @@ -2156,6 +2173,8 @@ def build_libstdcxx_dictionary ():
>      libstdcxx_printer.add_version('std::tr1::', 'unordered_multiset',
>                                    Tr1UnorderedSetPrinter)
>
> +    libstdcxx_printer.add_version('std::', 'initializer_list', StdInitializerListPrinter)
> +
>      # std::regex components
>      libstdcxx_printer.add_version('std::__detail::', '_State',
>                                    StdRegexStatePrinter)
> diff --git a/libstdc++-v3/testsuite/libstdc++-prettyprinters/cxx11.cc b/libstdc++-v3/testsuite/libstdc++-prettyprinters/cxx11.cc
> index 4262ca88b..621d13bd0 100644
> --- a/libstdc++-v3/testsuite/libstdc++-prettyprinters/cxx11.cc
> +++ b/libstdc++-v3/testsuite/libstdc++-prettyprinters/cxx11.cc
> @@ -25,6 +25,7 @@
>  #include <memory>
>  #include <iostream>
>  #include <future>
> +#include <initializer_list>
>  #include "../util/testsuite_allocator.h" // NullablePointer
>
>  typedef std::tuple<int, int> ExTuple;
> @@ -191,6 +192,11 @@ main()
>    std::error_code ecfut0 = std::make_error_code(std::future_errc{});
>    // { dg-final { note-test ecfut0 {std::error_code = {"future": 0}} } }
>
> +  std::initializer_list<int> emptyIl = {};
> +  // { dg-final { note-test emptyIl {std::initializer_list of length 0} } }
> +  std::initializer_list<int> il = {3, 4};
> +  // { dg-final { note-test il {std::initializer_list of length 2 = {3, 4}} } }
> +
>    placeholder(""); // Mark SPOT
>    use(efl);
>    use(fl);
> --
> 2.36.0
>